Highway spreaders for salt, sand, and cinders generally use hopper bodies. These have a bottom conveyor extending the full length of the body, which has sidewalls sloping down to the conveyor in hopper fashion. The conveyor feeds the load from the hopper out a rear opening to a spinner.
My experience shows many disadvantages in hopper bodies, including: they are expensive to purchase; they require full-length conveyors and must be available in several body and conveyor lengths; they take considerable time and labor to mount on a truck chassis or in a truck body; they are large and require considerable storage space when not in use; they raise the load to a high center of gravity, which is dangerous for the truck and driver; they cannot be dumped; they must be cleaned, sandblasted, and painted frequently; they retain corrosive salt in inaccessible places so that they rust out prematurely; they can clog with lumps and are dangerous to unclog; and because they are costly to remove and reinstall, they limit a truck to spreading duty when mounted and to non-spreading work when unmounted.
I have discovered a way of arranging a conveyor and spreader in a conventional dump truck body to accommodate both spreading and dumping and to achieve many advantages in economy, efficiency, and safety. My combination of a conveyor and spreader mounted in a conventional dump truck body aims at reliability, economy, ease of installation, safety, and versatility in operation.